////  BlockDownloader.h//  BlogComments////  Created by Xiaodong Chen on 11/20/10.//  Copyright 2010 Exigen Services SZ. All rights reserved.//#import <Foundation/Foundation.h>/*! @class BlockDownloader @abstract This class will be called to download resource from internet. */@interface BlockDownloader : NSObject {@private    CompletionBlock onCompletion;    ErrorBlock onError;	NSMutableData *activeDownload;    NSURLConnection *theConnection;}@property (nonatomic, retain)NSString* purpose;- (id)initOnCompletion:(CompletionBlock)completionBlock onError:(ErrorBlock)errorBlock;/*! @function startDownloadWithURL @abstract start to download the resource with url @param url resource url */- (void)startDownloadWithURL:(NSString*)url;/*! @function cancelDownload @abstract cancel the downloading cover icon. and also release resource */- (void)cancelDownload;@end